The frigate Thach, one of only five frigates still homeported in San Diego, recently fired its gun as part of a multi-nation military exercise off Brazil. The MK-75 76 mm gun is shown in this photo. The 28-year-old Thach, which is nearing the end of its service life, is operating in the Southern Seas, the Navy says. The Navy routinely refers to frigates as guided missile warships. But the missiles were removed from frigates in the 1990s as a cost-savings move. However, the helicopters carried by some frigates do stock missiles.

(Earlier version of story incorrectly said the gun was located at the front of the ship. It is not.)